Can caffeine cause a false positive for amphetamines?

I had a saliva drug test today and i am not a recreational drug user and have not taken any prescription medications for colds or flu but i returned a positive reading for amphetamines, the only thing i had in my system on the day was three cups of coffee, two cuppochinos that were in the packet style coffees, just add water and one plunger style coffee, the previous day i had drank six beers and two Apple ciders but no drugs licit or illicit of any kind, also i had eaten three meals throughout the day along with the alcohol.

What else could return a positive reading?